Which of the following is the nutrient-rich material commonly used to grow microbial cells in the laboratory?

• A. Agar
• B. Antibodies
• C. Antigens
• D. Bacteria

Answer: (A)

Verified step by step guidance

1. Understand the context of the question: it asks for a nutrient-rich material used to grow microbial cells in the laboratory.
2. Recall that microbial growth media provide essential nutrients like carbon, nitrogen, vitamins, and minerals to support the growth of microorganisms.
3. Identify the options given: Agar, Antibodies, Antigens, and Bacteria.
4. Recognize that Agar is a gelatinous substance derived from seaweed, commonly used as a solidifying agent in culture media, which supports microbial growth by providing a surface and nutrients when combined with other components.
5. Note that Antibodies and Antigens are related to immune responses, and Bacteria are the organisms themselves, not growth media.